The present invention relates generally to microwave devices, and more particularly, to a non-blocking, low loss waveguide switch for routing M-inputs to M of N-outputs.
Typical communication satellites use R-switches to route microwave signals. In fact, in most satellites, numerous R-switches are employed in a Butler matrix implementation to allow the routing of M-inputs to M of N-outputs. Unfortunately, each switch adds insertion loss and the matrix implementation has restrictions on port selection due to blocking. The size of the R-switch is important because as more switches are used weight and volume increases can result in large cost penalties. Also, the size of the R-switch can impose restraints on a transponder layout. A reduction in size and volume of R-switches can provide extra flexibility in the layout process while reducing the weight of the spacecraft payload.
Usually, an R-switch has three waveguide paths, a straight central path and two curved E-bend waveguide paths. In a variation of existing R-switches, the two outer paths have waveguide corners instead of curved E-bends. Generally, the waveguide corner R-switch has worse isolation and return loss performance compared to the E-bend R-switch. Also, the straight waveguide in the center path limits the amount of size reduction that can be achieved. R-switches are generally used in association with an actuator that moves the R-switch to various predetermined positions. Since there are numerous R-switches used in most communication satellites, any mass or volume saving can result in a substantial overall saving.
Thus, there exists the need to route M-inputs to M of N-outputs using fewer, smaller switches. Ultimately, the desire is to route M-inputs to M of N-outputs using as little weight and space as possible while maintaining system reliability and low insertion loss without blocking.
It is, therefore, an object of the invention to provide an improved and reliable non-blocking, low loss waveguide switch for routing M-inputs to M of N-outputs. Another object of the invention is to reduce insertion loss while eliminating blocking.
In one aspect of the invention, a satellite signal routing system includes a satellite using one or more waveguide switches for routing M-inputs to M of N-outputs. A waveguide switch includes a first waveguide, used as a stationary input coupled to a rotary joint. A joint rotation device, such as a motor, rotates the rotary joint. A rotary waveguide is attached to the rotary joint and also rotates. Two or more second waveguides, used as stationary outputs, are coupled to the rotary waveguide through a non-contacting waveguide. A controller controls the joint rotation device to rotate the rotary joint to align the rotary waveguide with one of the second waveguides.
The present invention thus achieves an improved non-blocking, low loss waveguide switch for routing M-inputs to M of N-outputs. The present invention is advantageous in that it improves system reliability by reducing the number of switches required. The present invention also eliminates restriction on port selection due to blocking.
Additional advantages and features of the present invention will become apparent from the description that follows, and may be realized by means of the instrumentalities and combinations particularly pointed out in the appended claims, taken in conjunction with the accompanying drawings.